Use CC as HOSTCC for building tools

[jhibbits]

Summary

U-boot uses HOSTCC to build the fixdeps utility, which should be the
same as CC. However, U-boot assumes HOSTCC is different from CC, as CC is
generally for the target, which is usually a different platform. In the case of
the u-boot-tools port, HOSTCC should be the same as CC, since it's not
generating anything to run on a separate target.

Test Plan

Compiled only

[manu]

Beside bumping PORTREVISION to 2 I'm ok with it.

[jhibbits]

Bump PORTREVISION